Relatives are considering instituting High Court proceedings later this month to block the development on Dublin's Moore Street, where the rebel leaders surrendered.

If successful, the legal action would most likely mean the commemorative facility would not be ready in time for the centenary of the Rising in two years' time.

Under a government-approved plan, only four buildings on the street will be preserved with national monument status for the commemoration facility, with the remainder giving way to a shopping centre planned by NAMA-controlled Chartered Land.

Mr Kenny has agreed to meet relatives today to discuss their concerns. The group is being supported by Sinn Fein leader Gerry Adams, former Labour junior minister Joe Costello and Independent TD Maureen O'Sullivan.

Jim Connolly Heron, the great-grandson of one of the Rising leaders, James Connolly, has said a much wider "battlefield" area should be preserved.

Reservations about the plan have also been expressed by two former directors of the National Museum.

The Department of Arts, Heritage and the Gaeltacht said it did not envisage the establishment of a formal museum, due to the size of the rooms.